Air-heating gas burner

ABSTRACT

A burner ( 10, 210, 310, 410 ) including a fuel manifold ( 12, 212, 312, 412 ), perforated air-mixing plates ( 14, 16, 214, 218, 414 ) coupled to the fuel manifold to define a fuel-air mixing region ( 22, 473 ) therebetween above the fuel manifold, and unperforated air-deflector wings ( 24, 26, 216, 236, 428 ). Each unperforated air-deflector wing is coupled to one of the perforated air-mixing plates such that each unperforated air-deflector wing extends upwardly from and at an angle to the perforated air-mixing plate to which it is coupled.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Application Ser. No. 60/236,295, filed Sep. 28, 2000, whichis expressly incorporated by reference herein.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to air-heating gas burners, andparticularly to a burner for burning a mixture of gaseous fuel andprocess air to heat the air for use in industrial applications. Moreparticularly, the present invention relates to a line burner assemblyincluding a fuel manifold and mixing plates mounted on the fuel manifoldand formed to include apertures through which process air passes to mixwith fuel discharged from the fuel manifold to produce a flame betweenthe mixing plates.

Line burner assemblies are able to burn a mixture including a gaseousfuel and air to produce a flame. Line burners are disclosed in U.S. Pat.Nos. 3,297,259; 4,869,665; and 5,131,836, which patents are herebyincorporated by reference herein. The disclosures in U.S. Pat. Nos.3,051,464; 3,178,161; and 4,573,907 are also hereby incorporated byreference herein.

It is known to provide elongated line burners which are formed toinclude a plurality of gaseous fuel openings and a plurality of airopenings along the length of the burner. Such line burners are known as“nozzle mix” line burners. Examples of nozzle mix line burners are shownin U.S. Pat. Nos. 4,340,180 and 4,403,947, which patents are herebyincorporated by reference herein.

It is also known to supply a premixed gaseous fuel and combustion airmixture to a manifold of a line burner and ignite the mixture to producea flame. Examples of “premix” line burners are shown in U.S. Pat. Nos.Re. 25,626; 3,178,161; 3,297,259; 4,573,907; and 4,869,665, whichpatents are hereby incorporated by reference herein.

Air-heating gas burners are well-suited to warm or temper incoming airinto buildings to relieve the building heating plant of peak or extraloads. They can be used to create a warm air curtain on open docks andfor process drying in industrial or agricultural applications.

Line burners are useful in various industrial applications where it isrequired to have a specific temperature distribution over apredetermined space or area. Examples of applications where line burnersare used include graphics applications, incinerators, turbine boosters,and board dryers. In a graphics application, for example, premix lineburners are used to generate hot air to dry ink or solvents fromprinting presses.

Process air is that air that is produced in a factory or industrialprocess and found to contain various inert matter entrained therein. Itis desirable to dispose of this process air in an environmentally soundway to minimize unwanted discharge of inert matter into the environment.One way to dispose of many of the contaminants entrained in process airis to incinerate it by burning a mixture of gaseous fuel and process airin a line burner. For example, process air containing solvents emittedfrom a printing press can be introduced into a line burner and mixedwith gaseous fuel to produce a flammable mixture. These entrainedsolvents are incinerated by the flame of the line burner as the processair passes through the mixing region of the line burner and the mixtureof gaseous fuel and process air is ignited. It is important that thismixture contain enough oxygen to kindle or sustain a flame.

According to the present invention, a line burner includes a fuelmanifold, a pair of perforated air-mixing plates coupled to the fuelmanifold to define a fuel-air mixing region therebetween above the fuelmanifold, and an unperforated air-deflector wing coupled to the top endof each air-mixing plate. The air-deflector wings are sized and arrangedto stimulate recirculation of combustion products back into the primaryreaction zone in the fuel-air mixing region to increase residence timeof combustion products in a high-temperature region of the flameproduced in the fuel-air mixing region.

In illustrative embodiments, the air-flow apertures formed in at leastsome of the air-mixing plates are sized, shaped, and spaced in a patternselected to improve aeration in the fuel-air mixing region. In a sectionof the aeration pattern, the apertures are arranged in rows and columns.With respect to the rows, the apertures nearer the side edges of theair-mixing plates are larger than the apertures nearer the middle of theair-mixing plates. With respect to the columns, the apertures becomesmaller going down each column.

In other illustrative embodiments, a burner includes an elbow-shapedmanifold and a wedge-shaped air-mixing plate mounted to the fuelmanifold to accommodate a turn of the fuel manifold. The wedge-shapedair-mixing plate includes first and second side edges that diverge awayfrom one another as they extend away from the fuel manifold.

Additional features of the invention will become apparent to thoseskilled in the art upon consideration of the following detaileddescription of illustrative embodiments of the invention exemplifyingthe best mode of carrying out the invention as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the accompanying figuresin which:

FIG. 1 is a perspective view of a line burner assembly in accordancewith the present disclosure showing a fuel manifold extending along thelength of the burner assembly between a pair of vertical end plates,four diverging perforated air-mixing plates anchored to the underlyingfuel manifold, and an angled air-deflector wing coupled to a top edge ofeach of the air-mixing plates;

FIG. 2 is a sectional view taken through the line burner assembly ofFIG. 1 showing the line burner assembly situated in a process air ductand various air and fuel supply and other apparatus associated with theline burner assembly;

FIG. 3 is an enlarged end elevation view of the line burner section ofFIG. 1 with the end plates removed showing the width and orientation ofthe unperforated air-deflector wings coupled to the top ends of thediverging air-mixing plates;

FIG. 4 is a diagrammatic view similar to FIG. 3 showing the pattern offlow of fuel and air around the line burner and showing how theunperforated air-deflector wings influence flow of combustion air andproducts of combustion to facilitate recirculation of combustionproducts back into the primary reaction zone to increase residence timeof combustion products in a high-temperature region of the flame;

FIG. 5 is an end elevation view of one of the air-mixing plates showingdimensions associated with the air-mixing plate along one side of theline burner assembly and a solid air-deflector wing coupled to the topend of that air-mixing plate;

FIG. 6 is a perspective view of a fuel discharge unit or manifoldincluded in the line burner of FIG. 1;

FIG. 7 is an end view of the fuel manifold shown in FIG. 6;

FIG. 8 is a side elevation view of an inner surface of the air-mixingplate shown in FIG. 5 as viewed in a direction suggested by line 8-8 ofFIG. 5 and showing a presently preferred pattern of air flow aperturesformed in the air-mixing plate;

FIG. 9 is a sectional view of one of the air-mixing plate aperturestaken along line 9-9 of FIG. 8;

FIG. 10 is a sectional view of another air-mixing plate aperture takenalong line 10-10 of FIG. 8;

FIG. 11 is a sectional view of yet another air-mixing plate aperturetaken along line 11-11 of FIG. 8;

FIG. 12 is a sectional view of still another air-mixing plate aperturetaken along line 12-12 of FIG. 8;

FIG. 13 is an enlarged view of a region A of the air-mixing plate ofFIG. 8 showing the size and arrangement of some of the apertures in theair-mixing plate;

FIG. 14 is a perspective view of another burner including a T-shapedfuel manifold, a pair of straight air-mixing plates coupled to themanifold, and a pair of corner air-mixing plates coupled to the fuelmanifold;

FIG. 15 is a perspective view of yet another burner including anH-shaped fuel manifold, straight air-mixing plates coupled to the fuelmanifold, and corner air-mixing plates coupled to the fuel manifold;

FIG. 16 is a perspective view of yet another burner including anelbow-shaped fuel manifold, straight air-mixing plates coupled to thefuel manifold, a corner air-mixing plate, and a wedge-shaped air-mixingplate;

FIG. 17 is a perspective view of the T-shaped fuel manifold of theburner of FIG. 14;

FIG. 18 is a perspective view of the H-shaped fuel manifold of theburner of FIG. 15;

FIG. 19 is a perspective view of the elbow-shaped fuel manifold of theburner of FIG. 16;

FIG. 20 is a top plan view of a corner air-mixing plate;

FIG. 21 is a side elevation view of the corner air-mixing plate of FIG.18;

FIG. 22 is an enlarged view of a region A of the corner air-mixing plateshown in FIG. 21;

FIG. 23 is an enlarged view of a region B of the corner air-mixing plateshown in FIG. 21;

FIG. 24 is an enlarged view of a region C of the corner air-mixing plateshown in FIG. 21;

FIG. 25 is an enlarged view of a region D of the corner air-mixing plateshown in FIG. 21;

FIG. 26 is an enlarged view of a region E of the corner air-mixing plateshown in FIG. 21;

FIG. 27 is a perspective view of the burner of FIG. 16, with the cornerair-mixing plate removed, showing a wedge-shaped air-mixing platepositioned at a turn of the elbow-shaped fuel manifold;

FIG. 28 is a side elevation view of the wedge-shaped air-mixing plate ofFIG. 27;

FIG. 29 is an end elevation view as viewed in a direction suggested byline 29-29 of FIG. 28;

FIG. 30 is an enlarged view of a region A of the wedge-shaped air-mixingplate shown in FIG. 29;

FIG. 31 is an enlarged view of a region B of the wedge-shaped air-mixingplate shown in FIG. 29; and

FIG. 32 is an elevation view as viewed in a direction suggested by line32-32 of FIG. 19 showing a plate spacer of the fuel manifold of FIG. 19.

DETAILED DESCRIPTION OF THE DRAWINGS

A line burner 10 is illustrated in FIGS. 1 and 2. Line burner 10includes a fuel manifold 12 and first and second air-mixing plates 14,16. End plates 18, 20 are positioned to lie at opposite ends of lineburner 10.

A mixing region 22 is provided above fuel manifold 12 to contain afuel-air mixture therein and support a flame upon combustion of thefuel-air mixture admitted into mixing region 22. Mixing region 22 isbounded in part by fuel manifold 12, air-mixing plates 14, 16, and endplates 18, 20.

Air-mixing plates 14, 16 are located on opposite sides of fuel manifold12 as shown, for example, in FIGS. 1-3. Each air-mixing plate 14, 16 isformed to include an array of air-flow apertures. In a preferredembodiment, the array of air-flow apertures is configured as shown inFIGS. 8 and 13 to create a more uniform flame and minimize “sooting”potential. Sooting means the formation of a black substance consistingof very small particles of carbon or heavy hydrocarbons resulting fromincomplete combustion.

Air-deflector wings 24, 26 are coupled to top edges 28, 30 of air-mixingplates 14, 16 as shown, for example, in FIGS. 1-5, and 8 and arranged insplayed relation to one another. Air-deflector wings 24, 26 arepositioned to lie between end plates 18, 20. Air-deflector wings 24, 26reshape a burner flame pattern to create a re-circulation of combustionproducts into the flame to increase fuel-air mixing effectiveness andcombustion intensity resulting in lower emissions and shorter flamelength.

Wings 24, 26 extend upwardly and away from mixing plates 14, 16. Eachair-deflector wing 24, 26 is unperforated and characterized by a width32 that extends from top edge 28 to outer wing edge 34 for air-deflectorwing 24 and that extends from top edge 30 to outer wing edge 36 forair-deflector wing 26. In a presently preferred embodiment, the width 32of each of air-deflector wings 14, 16 is about two inches as shown, forexample, in FIGS. 1, 2, and 5. Process air is manipulated and channeledby the unperforated air-deflector wings 24, 26 so that the air does notquench a flame produced in fuel-air mixing region 22 so as to minimizethe formation of nitrogen dioxide and carbon monoxide. This yields amore intense and compact flame.

Process (or other combustion) air 38 provided by combustion air supply39 is circulated through a duct 42 surrounding line burner 10 as showndiagrammatically in FIG. 2. Process air 38 moves around line burner 10as shown in FIGS. 2 and 4. A certain amount of process air 38 passesinto mixing region 22 formed in line burner 10 through the air-flowapertures formed in air-mixing plates 14, 16 as shown diagrammaticallyin FIG. 4.

Process air 38 typically contains a mixture of oxygen and inert gases.The process air passing into mixing region 22 mixes with gaseous fuel 41supplied to the mixing region through fuel-flow apertures 46 formed infuel manifold 12 to provide a combustible process air-and-fuel mixturein mixing region 22 of line burner 10. This combustible processair-and-fuel mixture is ignited to produce a flame 48 having roots inmixing region 22 as shown, for example, in FIG. 4.

A fan 50 is coupled to an outlet 52 formed in duct 42 to draw processair 38 to burner 10 and to discharge air heated in duct 42 to adestination away from duct 42 as shown in FIG. 2. It is within the scopeof this disclosure to place line burner 10 in any suitable environment.

Fuel manifold 12 includes a base 70, mounting flanges 72 at oppositeends of base 70, and a plate spacer 78 that is coupled to a top portionof base 70 as shown in FIGS. 6 and 7. Plate spacer 78 is positioned tolie between base portions 74, 76 of air-mixing plates 14, 16 as shown,for example, in FIGS. 2-4. Plate spacer 78 is characterized by a width80 extending laterally from one base portion 74 to another base portion76 as shown best in FIG. 3. In a presently preferred embodiment, platespacer width 80 is 1.062 inches as shown, for example, in FIGS. 6 and 7.Width 80 is wider in manifold 12 than in prior art manifolds. The widerwidth 80 associated with plate spacer 78 maximizes burner turndown andflame stability and attachment. Turndown is the ratio of the maximum andminimum firing rate for a particular burner where firing rate is themeasure of how much gaseous fuel is consumed per hour by a burner.

A fuel supply 54 is provided to supply gaseous fuel 41 to fuel manifold12 through fuel supply line 56 as shown diagrammatically in FIG. 2. Afuel transfer conduit 58 is formed in base 70 of fuel manifold 12 toreceive fuel 41 discharged from fuel supply line 56. Fuel transferconduit 58 is arranged to extend along the length of fuel manifold 12 tocommunicate with each of the fuel-flow apertures 46 formed in platespacer 78. As shown in FIG. 6, a series of fuel-flow apertures 46 isformed in plate spacer 78 to provide a fuel flow path to allow fuel topass from fuel transfer conduit 58 into the mixing region 22 locatedabove fuel manifold 12 and between air-mixing plates 14, 16.

Fuel transfer conduit 58 has an inner diameter of 1.88 inches and largervolume than prior art manifolds. This permits higher burner firing rateswithout increasing pressure drop or inlet pressure requirements.

Line burner 10 operates to minimize emission of carbon monoxide andnitrogen dioxide in the products of combustion by minimizing flamequenching through enhanced aerodynamic design resulting in improvedmixing of fuel and air. In direct-fired make-up-air heatingapplications, a large amount of air is heated to a relatively lowtemperature (e.g., less than 160° F.). The volume of air which flowsacross the burner is 3,000 to 4,000 times the amount of air required toburn the fuel completely. When an excessive amount of air is introducedinto the combustion zone, flame quenching occurs, causing flametemperatures to drop below the level necessary to completely oxidize thefuel molecules.

To prevent the products of combustion from being quenched or swept awayby the process air, line burner 10 includes unperforated air-deflectorwings 24, 26 at the outer ends of air-mixing plates 14, 16 to facilitatere-circulation of combustion products back into the primary reactionzone (as shown diagrammatically in FIG. 4), increasing residence time ofcombustion products in the high-temperature region of the flame.

Fuel manifold 12 includes a wide plate spacer 78 that is sized tomaximize the protected volume of the reaction zone and improve flamestability and flame attachment at the fuel discharge nozzles over a wideoperating range. The improved aerodynamics and flame attachment createsa more compact and intense reaction zone that minimizes flame quenching.Increased residence time at high temperatures and increased combustionintensity promotes the oxidation of carbon monoxide to carbon dioxideand minimizes formation of nitrogen dioxide.

Each of air-mixing plates 14, 16 includes a panel 180, as illustrated,for example, in FIG. 8. Each panel 180 is coupled to respectiveair-deflector wing 24, 26 and base portion 74, 76 and includesrespective top edge 28, 30, a first side edge 181, and a second sideedge 183.

A pair of upper side flanges 182 are coupled to either side of eachair-deflector wing 24, 26, as illustrated, for example, in FIGS. 3 and5. A pair of intermediate side flanges 184 are coupled to respectiveside edge 181, 183 of each panel 180. A pair of lower side flanges 186are coupled to either side of a panel 187 of respective base portions74, 76. Flanges 182, 184, 186 are formed to include apertures 188 sizedto received fasteners 190 to couple adjacent air-mixing plates 14, 16together or to couple an air-mixing plate 14, 16 to an end plate 18, 20.

Panel 180 of each air-mixing plates 14, 16 includes an array 92 ofapertures and an illustrative array is shown in FIG. 8. Array 92includes an upper section and a lower section, a portion of which isshown in FIG. 13. The upper section includes six domes 110 each formedto include a pair of apertures 111 (FIG. 11); a first set 112 ofprotrusion apertures (FIG. 9); a second set 113 of protrusion apertures(FIG. 8); a third set 114 of protrusion apertures (FIG. 12); a fourthset 115 of protrusion apertures (FIG. 12); a fifth set 116 of protrusionapertures (FIG. 10); apertures 117 (FIG. 8); apertures 118 (FIG. 8); andapertures 119 (FIG. 8).

Illustratively, the diameters of the apertures of the upper section ofarray 92 are as follows: six domes 110—0.312 inch; dome apertures111—0.124 inch; first set 112 of four protrusion apertures—0.344 inch;second set 113 of four protrusion apertures—0.161 inch; third set 114 offour protrusion apertures—0.312 inch; fourth set 115 of four protrusionapertures—0.312 inch; fifth set 116 of six protrusion apertures—0.188inch; five apertures 117—0.188 inch; two apertures 118—0.312 inch; andtwo apertures 119—0.250 inch. The height 171 of protrusion aperture 112is 0.120 inch (FIG. 9). The height 172 of dome 110 is 0.124 inch anddome 110 forms an angle 173 of 41°. The height 174 of protrusionaperture 115 is 0.120 inch.

A lower section of array 92 includes first, second, third, fourth,fifth, and sixth rows 120, 121, 122, 123, 124, and 125, respectively, ofapertures, as illustrated, for example, in FIGS. 8 and 13. Theseapertures are arranged in columns including first, second, third,fourth, fifth, sixth, seventh, and eighth columns 126, 127, 128, 129,130, 131, 132, and 133, respectively. With respect to each row, theapertures nearer side edges 181, 183 of each air-mixing plate 14, 16 arelarger than the apertures nearer a mid-line 153 to facilitate air flowthrough each air-mixing plate 14, 16 because this air flow may besomewhat inhibited by side flanges 182, 184, 186. With respect to thecolumns, the apertures become smaller going down each column. This isexemplified by illustrative dimensions now provided.

Illustratively, the diameters of the apertures of first row 120 is asfollows: first, second, seventh, and eighth columns 126, 127, 132,133—0.144 inch; third, fourth, fifth, and sixth columns 128, 129, 130,131—0.136 inch; and the other eight apertures—0.125 inch. The diametersof the apertures of second row 121 is as follows: first, second,seventh, and eighth columns 126, 127, 132, 133—0.140 inch; third,fourth, fifth, and sixth columns 128, 129, 130, 131—0.128 inch; and theother eight apertures—0.116 inch.

Illustratively, the diameters of the apertures of third row 122 is asfollows: first, second, seventh, and eighth columns 126, 127, 132,133—0.108 inch; third, fourth, fifth, and sixth columns 128, 129, 130,131—0.101 inch; and the other eight apertures—0.098 inch. The diametersof the apertures of fourth row 123 is as follows: first, second,seventh, and eighth columns 126, 127, 132, 133—0.101 inch; third,fourth, fifth, and sixth columns 128, 129, 130, 131—0.096 inch; and theother eight apertures—0.094 inch.

Illustratively, the diameters of the apertures of fifth row 124 is asfollows: first, second, seventh, and eighth columns 126, 127, 132,133—0.096 inch; third, fourth, fifth, and sixth columns 128, 129, 130,131—0.089 inch; and the other eight apertures—0.082 inch. The diametersof the apertures of sixth row 125 is as follows: first, second, seventh,and eighth columns 126, 127, 132, 133—0.082 inch; third, fourth, fifth,and sixth columns 128, 129, 130, 131—0.078 inch; and the other eightapertures—0.076 inch.

Base portion 74 is also formed to include a plurality of aperturesaligned with the columns of array 92, as illustrated, for example, inFIGS. 8 and 13. Illustratively, eight apertures 169 are aligned with thefirst through the eighth columns and have a diameter of 0.070 inch.Eight apertures 170 are aligned with the other columns and have adiameter of 0.063 inch.

Referring to FIG. 5, the following illustrative dimensions are provided:distance 134 between air-deflector wing 24 and base portion 74—6.000inches; distance 135 between apertures 136—1.500 inches; distance 137between lower aperture 136 and base portion 74—0.500 inch; angle138—22.50°; angle 139—45°; width 140 between top edge 28 and outer wingedge 34—2.000 inches; width 141 of outer flange 149—0.750 inch; distance142 between aperture 150 and an edge 151—0.250 inch; thickness 143 ofouter flange 149—0.036 inch; width 145 of base portion 74—1.125 inch;distance 146—0.750 inch; distance 147—0.250 inch; and distance 148—0.500inch.

Referring to FIG. 7, fuel manifold 12 includes the followingillustrative dimensions: distance 175—0.178 inch; distance 176—1.625inches; and distance 177—1.875 inches.

Referring to FIG. 8, the following illustrative dimensions are provided:

-   -   distance 152 between aperture 119 and mid-line 153—2.75 inches;        distance 154 between aperture 118 and mid-line 153—2.720 inches;        distance 155 between protrusion aperture 114 and protrusion        aperture 112—0.760 inch; distance 156 between adjacent        protrusion apertures 112—0.75 inch; distance 157 between        protrusion aperture 112 and mid-line—0.75 inch; distance 158        between dome 110 and aperture 119—0.313 inch; distance 159        between aperture 119 and aperture 114—1.125 inches; distance 160        between aperture 114 and aperture 117—0.938 inch; distance 161        between aperture 117 and first row 120—0.875 inch; distance 162        between first row 120 and second row 121—0.500 inch; distance        163 between second row 121 and third row 122—0.500 inch;        distance 164 between third row 122 and fourth row 123—0.406        inch; distance 165 between fourth row 123 and fifth row        124—0.375 inch; distance 166 between fifth row 124 and sixth row        125—0.312 inch; distance 167 sixth row 125 and bottom portion        74—0.250 inch; and width 168—5.940 inches. Three more burners        210, 310, and 410 are illustrated in FIGS. 14, 15, and 16,        respectively. Burner 210 includes a T-shaped fuel manifold 212        (see FIG. 17), burner 310 includes an H-shaped fuel manifold 312        (see FIG. 18), and burner 410 includes an elbow-shaped fuel        manifold 412 (see FIG. 19).

Each burner 210, 310, and 410 includes “straight” perforated air-mixingplates 214 configured as described previously with respect to perforatedair-mixing plates 14, 16. An air-deflector wing 216 configured asdescribed previously with respect to air-deflector wings 24, 26 iscoupled to each straight air-mixing plate 212.

Each burner 210, 310, and 410 includes one or more corner perforatedair-mixing plates 218 as well. Each corner air-mixing plate 218 isdescribed in more detail below. Each burner 210, 310, and 410 includesat least one corner 220 to which one corner air-mixing plate 218 iscoupled. T-shaped burner 210 includes a pair of corners 220 and a cornerair-mixing plate 218 is coupled to each corner 220 (see FIG. 14).H-shaped burner 310 includes four corner 220 and a corner air-mixingplate 218 is coupled to each one of those corners 220 (see FIG. 15).Elbow-shaped burner 410 includes a single corner 220 and a cornerair-mixing plate 218 is coupled to that corner 220 (FIG. 16).

Elbow-shaped burner 410 further includes a wedge-shaped air-mixing plate414, as illustrated, for example, in FIGS. 18, 19, and 28. Wedgeair-mixing plate 414 is supported by fuel manifold 412. Wedge air-mixingplate 414 is described in further detail below.

Fuel manifold 412 can be L-shaped, as illustrated, for example, in FIG.19, or can be configured to define an acute angle or an obtuse angle.Fuel manifold 412 includes a base 470 formed to include a curved fueltransfer passageway 471, mounting flanges 472 at opposite ends of base472, and a plate spacer 478 coupled to a top portion of base 470, asillustrated, for example, in FIG. 19. Base 470 and plate spacer 478cooperate to define a turn 477 of fuel manifold 412.

Plate spacer 478 is formed to include a plurality of fuel-flow apertures479 in communication with fuel transfer passageway 471 to dispense fuelinto a fuel-air mixing region 473 defined between air-mixing plates 214,218, 414, as illustrated, for example, in FIGS. 16 and 27.

Plate spacer 478 includes an inner portion 480 and an outer portion 482,as illustrated, for example, in FIGS. 19 and 32. Inner portion 480includes a first plate-engaging face 483 extending in a first directionand a second plate-engaging face 484 extending in a second direction.Corner air-mixing plate 218 is coupled to faces 483, 484. Outer portion482 includes a first plate-engaging face 485 extending in the firstdirection, a second plate-engaging face 486 extending in the seconddirection, and a third plate-engaging face 487 coupled to the first andsecond plate-engaging faces 485, 486, as illustrated, for example, inFIG. 32.

Straight air-mixing plates are coupled to the first and secondplate-engaging faces 485, 486 via fasteners 491 received withinapertures 490, as illustrated, for example, in FIGS. 16, 19, 27, and 32.Wedge air-mixing plate 414 engages the third plate-engaging face 487.

First and second plate-engaging faces 483, 484 cooperate to define partof inner portion 488 of turn 477. Inner portion 488 also defines part ofcorner 220 of fuel manifold 412. Third plate-engaging face 487 definespart of a turn outer portion 489 of turn 477. Corresponding portions ofbase 470 of fuel manifold 412 define the remainder of turn inner portion488 and turn outer portion 489.

Corner air-mixing plate 218 includes a first section 222 and a secondsection 224 coupled to first section 222 along an intermediate edge 226,as illustrated, for example, in FIG. 20. The structure of first andsecond sections 222, 224 are similar to one another so that thedescription of first section 222 applies also to second section 224,except as otherwise noted.

First section 222 includes a trapezoid-shaped panel 228 and a baseportion 230 coupled to a bottom edge 231 of panel 228, as illustrated,for example, in FIG. 21. Base portion 230 is coupled to the plate spacerof respective fuel manifold 212, 312, 412 to mount corner air-mixingplate 218 thereto. A side flange 232 is coupled to a side edge 234 ofpanel 228.

An air-deflector wing 236 is coupled to a top edge 238 of panel 228, asillustrated, for example, in FIGS. 20 and 21. Air-deflector wing 236 istrapezoid-shaped so that it includes an inner edge 240 coupled to topedge 238, an outer edge 242 parallel to and shorter than inner edge 240,and non-parallel side edges 244, 246. Side edge 244 of first section 222and side edge 244 of second section 224 are parallel to one another. Anouter flange 247 is coupled to and extends downwardly from outer edge242.

A side flange 248 is coupled to side edge 246. Side flanges 232, 248cooperate to define a connector 250, as illustrated, for example, inFIGS. 14-16. Connector 250 is configured to be coupled to an adjacentair-mixing plate.

Panel 228 is formed to include a plurality of apertures through whichair can flow, as illustrated, for example, in FIGS. 20 and 21. An uppersection of panel 228 is formed to include three circular domes 252 (FIG.26) each being formed to include a pair of dome apertures 253, a firstset 254 of protrusion apertures (FIG. 24), a second set 255 ofprotrusion apertures (FIG. 25), a third set 256 of protrusion apertures(FIG. 23), a fourth set 257 of protrusion apertures (FIG. 21), and otherapertures including a pair of upper apertures 258 (FIG. 21), anintermediate aperture 259 (FIG. 21), and a pair of smaller apertures 260(FIG. 21), as illustrated, for example, in FIGS. 20 and 21.

Illustratively, the diameters of the apertures of the upper section ofpanel 228 are as follows: dome apertures—0.070 inch; first set 254 ofprotrusion apertures—0.344 inch; a second set 255 of protrusionapertures—0.312 inch; a third set 256 of protrusion apertures—0.188inch; a fourth set 257 of protrusion apertures—0.161 inch; pair of upperapertures 258—0.250 inch; an intermediate aperture 259—0.312 inch; and apair of smaller apertures 260—0.188 inch.

A lower section of panel 228 is formed to include a plurality ofapertures including first, second, third, fourth, fifth, and sixth rows261, 262, 263, 264, 265, and 266, respectively, as illustrated, forexample, in FIGS. 21 and 22. The apertures of these rows are arranged ina plurality of columns including first, second, third, and fourthcolumns 267, 268, 269, and 270, respectively, which are nearest sideedge 234. With respect to each row, the apertures nearer side edge 234are larger than the apertures nearer intermediate edge 226 to facilitateair flow through corner air-mixing plate 218 because this air flow maybe somewhat inhibited by side flanges 232, 248. With respect to thecolumns, the apertures become smaller going down each column. This isexemplified by illustrative dimensions now provided.

Illustratively, the diameters of the apertures of first row 261 are asfollows: apertures of first and second columns 267, 268—0.144 inch;apertures of third and fourth columns 269, 270—0.136 inch; the other 8apertures—0.125 inch. The diameters of the apertures of second row 262are as follows: apertures of first and second columns 267, 268—0.140inch; apertures of third and fourth columns 269, 270—0.128 inch; theother 8 apertures—0.116 inch.

Illustratively, the diameters of the apertures of third row 263 are asfollows: apertures of first and second columns 267, 268—0.106 inch;apertures of third and fourth columns 269, 270—0.101 inch; the other 9apertures—0.098 inch. The diameters of the apertures of fourth row 264are as follows: apertures of first and second columns 267, 268—0.101inch; apertures of third and fourth columns 269, 270—0.098 inch; theother 9 apertures—0.093 inch.

Illustratively, the diameters of the apertures of fifth row 265 are asfollows: apertures of first and second columns 267, 268—0.098 inch;apertures of third and fourth columns 269, 270—0.089 inch; the other 10apertures—0.082 inch. The diameters of the apertures of sixth row 266are as follows: apertures of first and second columns 267, 268—0.082inch; apertures of third and fourth columns 269, 270—0.078 inch; theother 10 apertures—0.076 inch.

Base portion 230 is also formed to include a plurality of aperturesaligned with the columns of panel 228, as illustrated, for example, inFIGS. 21 and 22. Illustratively, the four apertures 271 aligned with thefirst four columns 267, 268, 269, 270 have a diameter of 0.070 inch andthe other 11 apertures 272 have a diameter of 0.064 inch.

A burner member 413 includes wedge air-mixing plate 414. Wedgeair-mixing plate 414 includes a trapezoid-shaped panel 417, a left sideflange 421 coupled to panel 417 along a left side edge 419, a right sideflange 420 coupled to panel 417 along a right side edge 422, and a baseportion 424 coupled to panel 417 along a bottom edge 426, asillustrated, for example, in FIGS. 27-29. Base portion 424 includes aleft side flange 425, a right side flange 429, and an intermediateportion 427 that is coupled to bottom edge 426 and abuts thirdplate-engaging face 487 of outer portion 482 of plate spacer 478.

Burner member 413 further includes an air-deflector wing 428 which iscoupled to a top edge 430, as illustrated, for example, in FIGS. 27-29.Air-deflector wing 428 is trapezoid-shaped so that it includes an inneredge 432 coupled to top edge 430, an outer edge 434 parallel to andlonger than inner edge 432, and non-parallel left and right side edges435, 436.

A left side flange 438 of burner member 413 is coupled to left side edge435 and a right side flange 440 of burner member 413 is coupled to aright side edge 436, as illustrated, for example, in FIG. 29. An outerflange 459 of burner member 413 is coupled to and extends downwardlyfrom outer edge 434.

Left side flanges 421, 425, 438 cooperate to define a left connector 442that is coupled to one of straight air-mixing plates 214 and one ofair-deflector wings 216. Right side flanges 420, 429, 440 cooperate todefine a right connector 444 that is coupled to the other of straightair-mixing plates 214 and the other of air-deflector wings 216. Baseportions 274 of straight air-mixing plates 214 are coupled to platespacer 478 of fuel manifold 412. Wedge air-mixing plate 414 is thuscoupled to fuel manifold 412 via the straight air-mixing plates 214.

Panel 417 is formed to include a plurality of apertures through whichair can flow, as illustrated, for example, in FIG. 28. An upper sectionof panel 417 includes four circular domes 448 (see also FIG. 30) eachbeing formed to include a pair of apertures 449, five protrusionapertures 450 (see also FIG. 31), and six side apertures 452. A lowersection of panel 417 includes six rows 453, 454, 455, 456, 457, and 458.

Illustratively, the diameters of the panel apertures are as follows:dome apertures 449—0.070 inch; protrusion apertures 450—0.161 inch; sideapertures 452—0.250 inch; first row 453—0.125 inch; second row 454—0.116inch; third row 455—0.098 inch; fourth row 456—0.094 inch; fifth row457—0.082 inch; sixth row 458—0.076 inch.

An illustrative tolerance for the dimensions detailed herein is +/−0.005inch, unless noted otherwise. For the diameters of the various aperturesdetailed herein, an illustrative tolerance is 0.010 inch. For angles, anillustrative tolerance is +/−1.

Although the invention has been disclosed in detail with reference tocertain illustrative embodiments, variations and modifications existwithin the scope and spirit of the invention as described and defined inthe following claims.

1. A burner comprising a fuel manifold, perforated air-mixing platescoupled to the fuel manifold to define a fuel-air mixing regiontherebetween above the fuel manifold, and unperforated air-deflectorwings, each unperforated air-deflector wing being coupled to a top edgeof one of the perforated air-mixing plates such that each unperforatedair-deflector wing extends upwardly from and at an angle to theperforated air-mixing plate to which it is coupled.
 2. The burner ofclaim 1, further comprising flanges, wherein each unperforatedair-deflector wing includes an inner edge coupled to the respectiveperforated air-mixing plate and an outer edge, and each flange iscoupled to the outer edge of one of the unperforated air-deflectorwings.
 3. The burner of claim 2, wherein each flange extends downwardlyfrom the respective outer edge.
 4. The burner of claim 1, wherein afirst of the unperforated air-deflector wings is rectangle-shaped. 5.The burner of claim 4, wherein a second of the unperforatedair-deflector wings is trapezoid-shaped.
 6. The burner of claim 1,wherein a first of the unperforated air-deflector wings istrapezoid-shaped.
 7. The burner of claim 6, wherein the first of theunperforated air-deflector wings includes an inner edge coupled to thetop edge of the respective perforated air-mixing plate and an outer edgeparallel to and longer than the inner edge.
 8. The burner of claim 6,wherein the first of the unperforated air-deflector wings includes aninner edge coupled to the top edge of the respective perforatedair-mixing plate and an outer edge parallel to and shorter than theinner edge.
 9. The burner of claim 6, wherein a second of theunperforated air-deflector wings is trapezoid-shaped and the first ofthe unperforated air-deflector wings and the second of the air-deflectorwings are coupled to the top edge of a first of the perforatedair-mixing plates.
 10. The burner of claim 9, wherein each of the firstof the unperforated air-deflector wings and the second of theunperforated air-deflector wings includes an inner edge coupled to thetop edge of the first of the perforated air-mixing plates, an outer edgeparallel to the inner edge, and a side edge coupled to the inner edgeand the outer edge, and the side edges are parallel to one another. 11.The burner of claim 10, wherein the inner edges are angled relative toone another and the outer edges are angled relative to one another. 12.A burner comprising a fuel manifold and air-mixing plates coupled to thefuel manifold to define a fuel-air mixing region therebetween above thefuel manifold, a first of the air-mixing plates including a first sideedge extending upwardly relative to the fuel manifold, the first of theair-mixing plates being formed to include a first row of apertures, thefirst row of apertures including a first aperture, a second aperture,and a third aperture, the first aperture being larger than and closer tothe first side edge than the second aperture and the third aperture, thesecond aperture being larger than and closer to the first side edge thanthe third aperture.
 13. The burner of claim 12, wherein the first row ofapertures includes a fourth aperture and the fourth aperture is the samesize as the first aperture and is positioned between the first apertureand the second aperture.
 14. The burner of claim 13, wherein the firstrow of apertures includes a fifth aperture and the fifth aperture is thesame size as the second aperture and is positioned between the secondaperture and the third aperture.
 15. The burner of claim 12, wherein thefirst of the air-mixing plates is formed to include a second row ofapertures including a fourth aperture, a fifth aperture, and a sixthaperture, the fourth aperture is larger than and closer to the firstside edge than the fifth aperture and the sixth aperture, and the fifthaperture is larger than and closer to the first side edge than the sixthaperture.
 16. The burner of claim 15, wherein the first aperture and thefourth aperture are arranged in a first column, the second aperture andthe fifth aperture are arranged in a second column, and the thirdaperture and the sixth aperture are arranged in a third column.
 17. Theburner of claim 16, wherein the first aperture is larger than the fourthaperture, the second aperture is larger than the fifth aperture, and thethird aperture is larger than the sixth aperture.
 18. The burner ofclaim 17, wherein the first row of apertures further includes a seventhaperture and an eighth aperture, the seventh aperture is the same sizeas the first aperture and is positioned between the first aperture andthe second aperture, the eighth aperture is the same size as the secondaperture and is positioned between the second aperture and the thirdaperture, the second row of apertures includes a ninth aperture and atenth aperture, the ninth aperture is the same size as the fourthaperture and is positioned between the fourth aperture and the fifthaperture, the tenth aperture is the same size as the fifth aperture andis positioned between the fifth aperture and the sixth aperture, theseventh aperture and the ninth aperture cooperate to define a fourthcolumn, and the eighth aperture and the tenth aperture cooperate todefine a fifth column.
 19. The burner of claim 12, wherein the first ofthe air-mixing plates includes a second side edge extending upwardlyrelative to the fuel manifold and the first row of apertures includes afourth aperture, a fifth aperture, and a sixth aperture, the fourthaperture is larger than and closer to the second side edge than thefifth aperture and the sixth aperture, and the fifth aperture is largerthan and closer to the second side edge than the sixth aperture.
 20. Theburner of claim 19, wherein the first aperture and the fourth apertureare the same size, the second aperture and the fifth aperture are thesame size, and the third aperture and the sixth aperture are the samesize.
 21. The burner of claim 12, wherein the first of the air-mixingplates is coupled to a corner of the fuel manifold and includes a firstpanel and a second panel angled relative to the first panel, the firstpanel is provided with the first side edge and the first row ofapertures, the second panel includes a second side edge extendingupwardly relative to the fuel manifold and is formed to include a secondrow of apertures positioned on a horizontal plane along with the firstrow of apertures, the second row of apertures includes a fourthaperture, a fifth aperture, and a sixth aperture, the fourth aperture islarger than and closer to the second side edge than the fifth apertureand the sixth aperture, and the fifth aperture is larger than and closerto the second side edge than the sixth aperture.
 22. The burner of claim21, wherein the first aperture and the fourth aperture are the samesize, the second aperture and the fifth aperture are the same size, andthe third aperture and the sixth aperture are the same size.
 23. Aburner comprising a fuel manifold, perforated air-mixing plates coupledto the fuel manifold to define a fuel-air mixing region therebetweenabove the fuel manifold, a first of the perforated air-mixing platesincluding a top edge, a first side edge, and a second side edge, thefirst side edge and the second side edge diverging away from one anotheras the first side edge and the second side edge extend away from thefuel manifold to the top edge.
 24. The burner of claim 23, wherein thefirst of the perforated air-mixing plates includes a perforated panelincluding a bottom edge adjacent to the fuel manifold and the top edge,the bottom edge, the first side edge, and the second side edge cooperateto define a trapezoid-shaped periphery of the perforated panel.
 25. Theburner of claim 24, wherein the top edge is longer than and parallel tothe bottom edge
 26. The burner of claim 23, wherein the first of theperforated air-mixing plates includes a first side flange coupled to thefirst side edge and a second side flange coupled to the second side edgeand the first side flange and the second side flange diverge away fromone another as the first side flange extends away from the first sideedge and the second side flange extends away from the second side edge.27. The burner of claim 23, wherein the fuel manifold is elbow-shaped sothat fuel manifold includes a turn including an inner portion and anouter portion and the first of the perforated air-mixing plates iscoupled to the outer portion.
 28. The burner of claim 23, furthercomprising an unperforated air-deflector wing extending upwardly fromthe top edge.
 29. The burner of claim 28, wherein the unperforatedair-deflector wing is trapezoid-shaped.
 30. The burner of claim 28,wherein the air-deflector wing includes an inner edge coupled to the topedge and an outer edge parallel to and longer than the inner edge. 31.The burner of claim 30, further comprising an outer flange coupled toand extending downwardly from the outer edge.
 32. A burner member for aburner including a fuel manifold and at least one perforated air-mixingplate coupled to the fuel manifold, the burner member comprising a baseportion adapted to be supported by the fuel manifold and a perforatedpanel adapted to cooperate with the at least one perforated air-mixingplate to define a fuel-air mixing region therebetween, the perforatedpanel being coupled to the base portion and including a top edge, afirst side edge, and a second side edge, the first side edge and thesecond side edge diverging away from one another as the first side edgeand the second side edge extend away from the base portion to the topedge.
 33. The burner member of claim 32, wherein the perforated panel iscoupled to the base portion along a bottom edge of the perforated paneland the top edge, the bottom edge, the first side edge, and the secondside edge cooperate to define a trapezoid-shaped periphery of theperforated panel.
 34. The burner member of claim 33, wherein the topedge is longer than and parallel to the bottom edge.
 35. The burnermember of claim 32, further comprising a first side flange coupled tothe first side edge and a second side flange coupled to the second sideedge and the first side flange and the second side flange diverge awayfrom one another as the first side flange extends away from the firstside edge and the second side flange extends away from the second sideedge.
 36. The burner of claim 32, further comprising an unperforatedair-deflector wing coupled to and extending upwardly from the top edge.37. The burner of claim 36, wherein the unperforated air-deflectorincludes an inner edge coupled to the top edge and an outer edgeparallel to the inner edge.
 38. The burner member of claim 37, furthercomprising an outer flange coupled to and extending downwardly from theouter edge.
 39. A burner comprising a fuel manifold and a plurality ofperforated air-mixing plates coupled to the fuel manifold to define afuel-air mixing region therebetween, the fuel manifold beingelbow-shaped.
 40. The burner of claim 39, wherein the fuel manifold isL-shaped.
 41. The burner of claim 39, wherein the fuel manifold includesa base formed to include an L-shaped fuel transfer passageway.
 42. Theburner of claim 39, wherein the fuel manifold includes a plate spacercoupled to the plurality of perforated air-mixing plates and formed toinclude a plurality of fuel-flow apertures to dispense fuel into thefuel-air mixing region and the plate spacer turns from a first directionto a second direction.
 43. The burner of claim 42, wherein the platespacer includes an outer portion coupled to some of the air-mixingplates and an inner portion coupled to some of the air-mixing plates andeach of the outer portion and the inner portion turns from the firstdirection to the second direction.
 44. The burner of claim 43, whereinthe outer portion includes a first plate-engaging face extending in thefirst direction and a second plate-engaging face extending in the seconddirection.
 45. The burner of claim 44, wherein the outer portionincludes a third plate-engaging face coupled to the first plate-engagingface and the second plate-engaging face.
 46. The burner of claim 43,wherein the inner portion includes a first plate-engaging face extendingin the first direction and a second plate-engaging face extending in thesecond direction.
 47. A fuel manifold for a burner including a pluralityof perforated air-mixing plates that can be coupled to the fuel manifoldto define a fuel-air mixing region therebetween, the fuel manifoldcomprising a base formed to include a fuel transfer passageway and aplate spacer coupled to the base and adapted to be coupled to theperforated air-mixing plates, the plate spacer being formed to include aplurality of fuel-flow apertures in communication with the fuel transferpassageway to dispense fuel into the fuel-air mixing region, the baseand the plate spacer being elbow-shaped.
 48. The fuel manifold of claim47, wherein the base and the plate spacer are L-shaped.
 49. The fuelmanifold of claim 47, wherein the plate spacer includes an outer portionadapted to be coupled to some of the air-mixing plates and an innerportion adapted to be coupled to some of the air-mixing plates and eachof the outer portion and the inner portion turns from a first directionto a second direction.